PROJECT SUMMARY Morbidity and mortality related to prescription opioids is accelerating in the United States. Existing strategies to address prescription opioid misuse primarily target the downstream effects of chronic opioid dependence, such as non-medical prescription opioid and heroin abuse. However, identifying the factors that lead to new opioid dependence among opioid nave patients is a critical opportunity to reduce prescription opioid dependence and unintended diversion. In the United States, the majority of individuals who become opioid dependent receive their first opioid prescription following surgical procedures (elective surgery, emergent surgery, and trauma); yet, there are no clinical guidelines to inform appropriate postoperative opioid use. [We hypothesize that measurable patient factors will predict increased postoperative opioid consumption and that most patients will be prescribed opioids far in excess of their needs]. We further hypothesize that current opioid prescribing patterns do not correlate well with patient-reported pain, and are predicated upon surgeon experience and preferences. [In this context, an intervention that provides personalized data to providers regarding opioid prescribing and consumption (e.g. type, number of pills, refills) coupled with patient-reported opioid consumption will reduce inappropriate opioid prescriptions and diversion to unintended users. In this mixed- methods study, we will examine the patient factors that are associated with postoperative pain and opioid consumption among a cohort of patients undergoing five common, elective, abdominal procedures.] [Additionally, we will identify the provider characteristics that underlie the variation in postoperative opioid prescribing practices, and will design and implement a provider-directed intervention to optimize postoperative opioid prescribing. To do this, we will leverage the existing infrastructure of the Michigan Surgical Quality Collaborative program, a state-wide consortium of 73 hospitals that is funded by Blue Cross and Blue Shield (BCBS) of Michigan.] This clinician-led collaborative quality improvement program engages nearly all providers who perform major inpatient general and vascular surgery procedures with a robust framework equipped to collect detailed clinical information, identify best practices and opportunities for improvement, and rapidly disseminate quality initiatives. Findings from this multifaceted, population-based study will inform patients and providers regarding the risk of opioid dependence following surgery, and will establish a patient-centered data infrastructure that yields continuous feedback to providers regarding appropriate opioid prescribing practices. As the prescription opioid epidemic intensifies, strategies to prevent new opioid dependence have the greatest potential to reduce opioid-associated morbidity and mortality. This 5-year project will derive the necessary evidence to inform guidelines regarding effective and appropriate postoperative pain management, and will identify opportunities to both reduce the risk of iatrogenic opioid dependence following surgery and prevalence of prescription opioid diversion to unintended users.